Regulation of NF-E2 activity in erythroleukemia cell differentiation.
The erythroid transcription factor NF-E2 is an obligate heterodimer composed of two different subunits (p45 and p18), each containing a basic region-leucine zipper DNA binding domain, and it plays a critical role in erythroid differentiation as an enhancer-binding protein for expression of the beta-globin gene. We show here that dimethyl sulfoxide treatment of wild-type murine erythroleukemia cells, but not a mutant clone of dimethyl sulfoxide-resistant cells, increases NF-E2 activity significantly, which involves both up-regulation of DNA binding and transactivation activities. Both activities were reduced markedly by treatment of cells with 2-aminopurine but not by genistein. Activation of the Ras-Raf-MAP kinase signaling cascade increased NF-E2 activity significantly, but this was suppressed when MafK was overexpressed. Domain analysis revealed an activation domain in the NH2-terminal region of p45 and a suppression domain in the basic region-leucine zipper of MafK. These findings indicate that induction of NF-E2 activity is essential for erythroid differentiation of murine erythroleukemia cells, and serine/threonine phosphorylation may be involved in this process. In addition, they also suggest that a MafK homodimer can suppress transcription, not only by competition for the DNA binding site, but also by direct inhibition of transcription. Hence, MafK may function as an active transcription repressor.
Nagai
T
T
Rockefeller University, New York, New York 10021, USA.
Igarashi
K
K
Akasaka
J
J
Furuyama
K
K
Fujita
H
H
Hayashi
N
N
Yamamoto
M
M
Sassa
S
S
D000624:5-Aminolevulinate Synthetase / Q000096:biosynthesis; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004351:Drug Resistance / Q000235:genetics; D004742:Enhancer Elements, Genetic; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D015973:Gene Expression Regulation, Leukemic; D005914:Globins / Q000096:biosynthesis; D006418:Heme / Q000032:analysis; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics*; D050985:MafK Transcription Factor; D051379:Mice; D008957:Models, Genetic; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers; D018631:ras Proteins / Q000378:metabolism
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050985:MafK Transcription Factor; C494696:Mafk protein, mouse; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; C494693:Nfe2 protein, mouse; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D006418:Heme; D005914:Globins; D000624:5-Aminolevulinate Synthetase; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D018631:ras Proteins; D004121:Dimethyl Sulfoxide